The words “I was wrong” do not often pass through the lips of Rick Perlstein, the famously pugnacious left-wing historian of American conservatism. It grabbed attention, then, when that confession headlined Perlstein’s contribution to The New York Times Magazine this week: “I thought I understood the American Right. Trump Proved Me Wrong.”

The content of the confession proved less repentant than the headline. Perlstein’s three books—about Barry Goldwater, Richard Nixon, and Ronald Reagan—depicted an American right that was morally and intellectually repellent: reactionary, racist, and rapacious. The election of Donald Trump, however, forced Perlstein to rethink and to realize that he had dangerously understated the case, and that the truth was even more appalling than anything he had yet dared to think or write.

I quote intermittently and in some cases a little out of context, but the cumulative effect gives an idea:

"America’s anti-liberal traditions were far more deeply rooted in the past, and far angrier, than most historians would acknowledge.”

"By reaching back to the reactionary traditions of the 1920s, we might better understand the alliance between the “alt-right” figures that emerged as fervent Trump supporters during last year’s election and the ascendant far-right nativist political parties in Europe.”

“Far-right vigilantism and outright fascism routinely infiltrated the mainstream of American life.”

“'Fascism had a very real presence in the U.S.A., comparable to that on continental Europe.”

Along the way, Perlstein name-checks currently active conservative journalists Jonah Goldberg, Andrew McCarthy, and Lisa Schiffren as exemplars of the continuing dark tradition of right-wing awfulness. Everything else that has been called “conservatism” in the 20th century—from Robert Taft to Mitt Romney—is so much misdirection, false consciousness, or outright deception. "The history of bait-and-switch between conservative electioneering and conservative governance,” Perlstein writes, “is another rich seam that calls out for fresh scholarly excavation.”

Perlstein does himself one injustice in his essay. It’s not quite right that the rise of Donald Trump jolted him into a new appreciation of the Republican Party’s underlying fascism. He has been edging toward that accusation for years, to the increasing consternation of those who praised his first book.

George Packer's review in The New Yorker of Perlstein's third book noted Perlstein’s trajectory.

In his accounts of the sixties, Perlstein had a more complex view of the decade’s political passions—he took pains to understand the mental world inhabited by Goldwater, Nixon, and their partisans. … But, as the story of modern conservatism moves toward the present, Perlstein’s attitude toward it begins to resemble the dismissiveness of those liberal critics, which takes some of the tension out of his dialectics.

In our own pages, Sam Tanenhaus offered a similar criticism of that book.

Perlstein’s gift for energetic caricature and his taste for bizarre incidents have overpowered his impulse to sift through the ideas and beliefs that animate his subjects, and to grapple seriously with a politics rooted in authentic if not always coherent dissent.

The deterioration has only accelerated since then, and it’s worth considering why—not to score points off Perlstein, but to think more deeply together about how (and how not) to do intellectual history.

It’s certainly true that the United States has noteworthy traditions of illiberalism and political violence. The 1920s suffered terrorist violence not only at the hands of the Ku Klux Klan, but also those of anarchist bombers who maimed and killed hundreds of people from 1919 to 1921. From the Civil War to World War II, American labor relations were more violent than those of most other industrialized countries. Four presidents have been assassinated; four others—Theodore Roosevelt, Franklin Roosevelt, Gerald Ford, and Ronald Reagan—only narrowly survived or escaped a bullet. Race riots have ripped apart American cities for almost as long as there have been American cities.

Donald Trump’s campaign for president certainly drew much energy from this long tradition of political violence. So too did some of Trump’s opponents: Protests in Washington, D.C. on Trump’s Inauguration Day did damage to property, sent two police officers to hospital, and led to 200 arrests. Smaller scale versions of this form of violent protest have targeted colleges—notably Berkeley and Middlebury—that have invited speakers whom rioters deemed sympathetic to Trump’s cause.

So Perlstein is talking about something real. The trouble is the polemical use he wants to make of this reality.

Perhaps a counter-example will clarify the problem.

When conservatives want to rebut accusations of racism, they often deploy the talking point: The Ku Klux Klan—meaning the Klan of the 1860s and 1870s—was founded by Democrats. Rand Paul built a speech at Howard University on the claim; Dinesh D’Souza produced an entire documentary to illustrate it.

The “Democrats founded the Klan” talking point is, of course, literally true. But it’s not deployed in the service of truth. It’s designed as an excuse and an attack, not an explanation.

And so it is with Perlstein’s trope about Trump and the Klan of the 1920s. It’s an important question whether the success of Donald Trump—and the rise of similar authoritarian populists in France and elsewhere in Europe—is the recrudescence of something old or the appearance of something new. The more worried you are about Trump and Trumpism, the more urgent this question should be to you—because only the correct answer will lead to a wise response.

Somehow an explanation of Donald Trump’s political success has to incorporate the fact that Trump won a higher share of the Latino vote and black vote in the presidential election of 2016 than Mitt Romney did in 2012- and that Hillary Clinton did worse with white voters than Barack Obama had done. There’s little question that inter-ethnic animosity explains much about the 2016 vote. But it seems simply blind to pretend that these animosities straightforwardly carry over into 2016 the attitudes and patterns of almost a century ago. The study of continuity and discontinuity is literally the historian’s job. When the historian instead baldly asserts that anything he dislikes is the same as everything else he dislikes—well, then the job of the historian is abdicated.

At the foundation of Perlstein’s intellectual dilemma is the following paradox. Perlstein strongly identifies as a political progressive. Fine for him, it’s a free country. Contemporary progressivism values both cultural cosmopolitanism and also economic egalitarianism; both diversity and equality. People strongly committed to progressive politics can readily take for granted that their two deepest commitments inherently and necessarily belong together. But that’s really not true.

Through most of the history of ideas, the great champions of equality have been xenophobes—not out of bigotry, but because they believed that only a tightly bonded society could suppress the concentration of wealth in the hands of a few. Let Jean-Jacques Rousseau speak for a tradition that commenced with the Greeks and continued to the Jacobins and beyond: The best leaders determine “that his people should never be absorbed by other peoples” and therefore “devised for them customs and practices that should could not be blended into those of other nations.” Ideally: “Each fraternal bond … among the individual members of his republic became a further barrier, separating them from their neighbors and keeping them from becoming one with those neighbors,” he wrote in his Considerations on the Government of Poland. As for more cosmopolitan societies, Rousseau had this disdainful comment in The Social Contract: “The people has less affection for the homeland which is like the whole world in its eyes, and for its fellow citizens, most of whom are foreigners to it.”

Those who have delighted in cosmopolitanism, by contrast, have historically attached little importance to equality. “We continue still to repine,” wrote David Hume, "that our neighbours should possess any art, industry, and invention; forgetting that, had they not first instructed us, we should have been at present barbarians; and did they not still continue their instructions, the arts must fall into a state of languor, and lose that emulation and novelty, which contribute so much to their advancement.” This instruction was obtained by trade—and of course trade brings inequality with it. "Commerce encreases industry, by conveying it readily from one member of the state to another, and allowing none of it to perish or become useless,” Hume wrote. “It encreases frugality, by giving occupation to men, and employing them in the arts of gain, which soon engage their affection, and remove all relish for pleasure and expence. It is an infallible consequence of all industrious professions, to beget frugality, and make the love of gain prevail over the love of pleasure.”

In American history too, the great egalitarians, like William Jennings Bryan, have often been cultural chauvinists; the great cosmopolitans, like Alexander Hamilton, usually indifferent or hostile to economic equality.

We have observed a very different pattern over the past 40 years, of course. But one thing that seems to have happened in the Trump era is that this familiar pattern has suddenly become unstable. The component parts of the American electorate seem in flux. The wealth and power of the country are moving into the column of the party supposedly of redistribution; disappointment and despair into the party supposedly of enterprise.

The Second Klan of the 1920s originated in the Deep South, then rapidly spread after 1919 into the then most dynamic regions of the country: New York and Long Island; Detroit and Pittsburgh: Philadelphia and the anthracite Belt; the Pacific Northwest and Los Angeles. The Trump vote, by contrast, is concentrated in the least dynamic areas of the country. The 2,600 counties won by Trump produce only about one-third of America’s wealth. Trump did well where people suffer most from diabetes, and where opiate overdoses take most lives. The Second Klan offered a defiant cultural counter-revolution; the Trump vote could be seen as the despair of defeated people—something more like the William Jennings Bryan candidacies.

If this analysis is correct, then the appropriate source of concern for the American future is not Trump’s duped voters, but the politician who did the duping—and the story to tell is not that of the remorseless rise of fascism in the people, but the failure of popular institutions to resist and contain the ambitions and impulses of a charismatic authoritarian without a popular mandate.

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